Simmani: Runtime Power Modeling for Arbitrary RTL with Automatic Signal Selection

This paper presents a novel runtime power modeling methodology which automatically identifies key signals for power dissipation of any RTL design. The toggle-pattern matrix is constructed with the VCD dumps from a training set, where each signal is represented as a high-dimensional point. By clustering signals showing similar switching activities, a small number of signals are automatically selected, and then the design-specific but workload-independent activity-based power model is constructed using regression against cycle-accurate power traces obtained from industry-standard CAD tools. We can also automatically instrument an FPGA-accelerated RTL simulation with runtime activity counters to obtain power traces of realistic workloads at speed. Our methodology is demonstrated with a heterogeneous processor composed of an in-order core and a custom vector accelerator, running not only microbenchmarks but also real-world machine-learning applications.